NEW YORK – The owners of nearly 1,300 large New York City buildings converted from oil to natural gas in 2013, choosing a less expensive, cleaner heating fuel.

The number of large buildings making the switch has grown each year since the city passed its NYC Clean Heat regulations in 2011. That year, 309 buildings converted from No. 4, No. 6 and No. 2 oil. In 2012, 855 buildings converted, and last year 1,293 switched.

The city regulations require customers to stop using No. 6 oil by 2015 and to stop using No. 4 oil by 2030. Though the regulations do not require buildings to stop burning No. 2 oil, many of those customers are making the change to natural gas too, due to natural gas being cheaper on average and more efficient.

Anticipating more growth, Con Edison plans to invest $1.73 billion on gas infrastructure over the next three…